Sunday, September 17, 2006

How Pressure Treated Wood is Pressure Treated

People often ask how wood is pressure treated so the purpose of this article is to provide the basics of the process - the elevator speech on pressure treating wood.

Pressure Treating Wood

Currently, the two most popular pressure treatment chemicals in use are CCA (Chromated Copper Arsenate) and ACQ (Alkaline Copper Quaternary). Both treatments are actually solid compounds. Water is used in the pressure treating process to carry the compounds into the wood.

The wood to be treated is put into a large sealed horizontal treating cylinder in which the water carrying the preservative chemical is pumped, surrounding the wood. Pressure is applied inside the cylinder to force the waterborne wood preservatives into the cellular structure of the wood until the desired retention level is reached.

Next, the treating chemical is pulled from the treating cylinder and stored in another tank to be reused. A vacuum is then applied to the treating cylinder to pull excess water from the wood. The wood is removed from the cylinder and allowed to air dry outside, maybe with fans, or it might even be put into a kiln.

Slight alterations to the procedure may be required based on what the wood will be used for and what level of retention is required but the overall process is the same.

Pressure Treating wood is not rocket science but does require specialized equipment, expertise, is highly regulated, adds a great deal of value to the wood, and helps the environment by prolonging the life of lumber and preventing the need to replace that wood by cutting additional trees in the future.

More Information on Custom Home Building at: Ontario Home Builder